New field observations on the competitive displacement between two species of planorbid snails inhabiting Northeastern Brasil

Observations reported in the present paper have shown that Biomphalaria glabrata is being gradually displaced by B. straminea in coastal areas of two counties on the state of Pernambuco, Brazil, confirming former observations made in the same region.Observações apresentadas neste trabalho mostram que Biomphalaria glabrata esta sendo gradualmente deslocada por B. straminea em dois municípios do Estado de Pernambuco, Brasil, confirmando observações anteriores feitas na mesma região